JPH0333479A - Guide vane control device of hydraulic wheel - Google Patents

Abstract

PURPOSE:To reduce the capacity of a motor by installing V-belt wheels with the spacing variable on the rotary shaft of the motor and a ball screw shaft meshing with a guide vane opening/closing lever, and setting a belt over these wheels for reducing the speed. CONSTITUTION:V-belt wheels 6, 8 are installed on the rotary shaft 1a of a motor 1 and a ball screw shaft 3 meshing with a guide vane opening/closing lever 4. These belt wheels 6, 8 are formed from mutually mating two conical discs 6a, 6b and 8a, 8b, and between them a belt 10 is set over to constitute a speed reduction mechanism. The conical discs 6a, 8a are secured to the shafts 1a, 3, and the conical disc 6b is energized by a spring 7 in the direction of going apart from the conical disc 6a while the conical disc 8b energized by a spring 9 in the direction of approaching the conical disc 8a. Solenoids 11, 12 secured to the conical discs 6b, 8b are demagnetized at normal time, and the gear ratio is enlarged to increase the torque. The solenoids 11, 12 are magnetized when the vane is shut quickly, so as to decrease the gear ratio. This allows accomplishing the motor in a small size.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a guide vane control device for a water turbine in a hydroelectric power plant or the like.

(Prior art) Traditionally, the rotational speed control of water turbines in hydroelectric power plants, known as governor control, has been carried out by operating guide vanes using hydraulic pressure. Guide vane operation methods using electric servo motors, which do not cause any negative effects, are increasingly being adopted.

FIG. 3 is a diagram showing an electric servo motor used for operating the guide vane, in which the output shaft 1a of the electric motor 1 is interlocked and connected to the ball screw shaft 3 via a reduction gear device 2. The proximal end of a guide vane opening/closing operating rod 4 whose tip end is connected to a guide ring (not shown) for opening/closing the guide vane is screwed together.

When the electric motor 1 rotates, the speed is reduced by the reduction gear device 2, the torque is increased, and the ball screw shaft 3 is rotationally driven. Therefore, the rotational force of the ball screw shaft 3 is transferred to the guide vane opening/closing operation rod 4 in an efficient straight line. This linear motion force opens and closes the guide vanes.

(Problems to be Solved by the Invention) However, generally, the gas vane as a load connected to this electric servo motor has a self-closing characteristic for fail-safe purposes when the power source 11i is used. That is, as shown in FIG. 4, a force in the direction of closing the guide vane acts on the guide vane over most of the range except near the fully opened position. Therefore, force is required to open the guide vane, but less force is required to close it.

In addition, in water turbine control, the opening/closing time and closing time of the guide vanes are different, and generally the opening time is set to about 30 seconds to 19 seconds to prevent the casing from becoming negative pressure and crushing due to flowing water, and the closing time is about 19 seconds. The period between 11 and 7 is relatively short, about several seconds, in order to suppress the maximum rotational speed of the water turbine. Therefore, the characteristics required of the electric servo motor are that when the guide vane opens <Il, '7, it operates slowly with a large force, and when it closes, it operates quickly with a small force.

Therefore, the capacity of the electric servo motor is determined by the maximum torque when the guide vane is opened and the maximum speed when the guide vane is closed. Therefore, there are problems such as the motor capacity inevitably becoming too large and the motor becoming larger.

SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to provide a guide vane control device that can perform torque-rotation speed control in accordance with the characteristics of the guide vane, which is a load.

[Structure of the invention]

(Means for Solving the Problems) The present invention connects the output shaft of the electric motor and the ball screw shaft into which the operation rod for opening and closing the guide vane is screwed, by changing the interval between the conical plates facing each other to change the working diameter of the belt. It is characterized by being interlocked and connected via a speed reduction device consisting of a variable V-type belt pulley.

(Function) At the time of sudden shutdown such as load shedding, the interval between both conical plates of the belt pulley on the motor side is narrowed, the interval between both conical plates of the belt pulley on the ball screw side is widened, and the reduction ratio in the reduction gear is reduced. Ru. Therefore, the closing of the guide vanes takes place at a high speed. -h, During the normal guide vane closing operation and guide vane opening operation, the speed ratio is increased by adjusting the interval between both conical plates, and a large torque is generated.

(Example) Hereinafter, an example of the present invention will be described with reference to FIGS. 1 and 2.

In FIG. 1, reference numeral 1 denotes an electric motor for controlling the opening and closing of the guide vane, and the output shaft 1a of the electric motor 1 is connected to a ball screw shaft 3 to which the base end of the operating rod 4 for opening and closing the guide vane is screwed. A speed reduction device 5 consisting of a variable V-type belt pulley is interposed between the two.

That is, FIG. 2 is an enlarged view of the 5 parts of the speed reduction device,
A pair of conical plates 6a and 6b are mounted on the output shaft 1a of the electric motor 1 so that their conical surfaces face each other. By the way, one male plate 6a is fixed to the output shaft 1a, and the other conical plate 6b is mounted so as to be movable in the axial direction with respect to the output shaft 1a. 7 in a direction away from the conical plate 6a. That is, at normal times, both conical plates 6a
, 6b are widened.

On the other hand, the ball screw shaft 3 also has a pair of conical plates 8a, 8.
b is attached, and only one conical plate 8b is connected to the ball screw shaft 3.
Both conical plates 8a are movable along the same axis, and are normally supported by springs 9.

8b is biased so that the distance between them becomes narrower.

A belt 1 is placed between a belt pulley 6 made up of a pair of conical plates 6a and 6b and a belt pulley 8 made up of conical plates 8a and 8b.
0 is wrapped.

In addition, electromagnetic solenoids 11 and 12 are provided at the ends of the output 1*1a and the ball screw shaft 3, respectively, and when the electromagnetic solenoid 11 is excited, the spacing between the conical plates 6a and 6b of the belt pulley 6 is reduced by the spring 7. narrowed against the
When the electromagnetic solenoid 12 is excited, the distance between the conical plates 8a and 8b of the belt pulley 8 is expanded against the force of the spring 9.

That is, solenoid magnets 118.12a are fixed to the conical plates 6b and 8b, respectively, and solenoid coils 118.12a are fixed to the cases 13.14, which respectively support the output shaft 1a and one end of the ball screw shaft 3.
2b is installed, and the above solenoid coil llb, 12b
When the solenoid magnet 11a is excited, the solenoid magnet 11a moves to the right in the figure, and the solenoid magnet 12a moves to the left in the figure.

Therefore, under normal conditions, both electromagnetic solenoids 11.1
2 solenoid coils 11b and 12b are demagnetized, and in the belt pulley 6 on the motor side, both conical plates 6a and 6b are demagnetized.
The interval between the two conical plates 8a is widened, and the working diameter of the belt 10 is small.

8b is narrowed by the spring 9, and the belt 1
0 is in a state where the working diameter is large. Therefore, the reduction ratio between both belt pulleys 6.8 is large, and the belt pulley 6.8 is used in a state where the torque is large.

On the other hand, in the event of sudden closure due to load shedding, etc., a large closing command is issued from the speed governor control device, and this command causes the solenoid coils llb and 12b of both electromagnetic solenoids 11 and 12 to
is excited. Therefore, in the belt pulley 6, both conical plates 6
The distance between a and 6b is narrowed to increase the working diameter of the belt, while in the other belt pulley 8 the distance between both conical plates 8a and 8b is widened to reduce the working diameter of the belt. This reduces the reduction ratio between both belt pulleys 6.8, allowing the guide vanes to close at high speed. In this case, the output torque will be small, but as shown in FIG. 4, the torque is not necessary, so there is no problem.

In the above embodiment, a single speed reduction stage is shown, but it goes without saying that a plurality of speed reduction stages may be used as required. Further, if the spring 9 that urges the conical plates 8a and 8b to narrow the interval is a tension spring, the structure of the conical plate 8a can be the same as that on the output shaft side.

〔Effect of the invention〕

Since the present invention is configured as described above, the speed-torque characteristic can be set to match the load characteristic of the guide vane, and the motor capacity can be reduced.

Therefore, it is economical and the application of the electric servo motor can be expanded to larger hydroelectric power plants. In addition,
If each conical plate is actuated by an electromagnetic solenoid as in the example, and the reduction ratio is made smaller when the electromagnetic solenoid is demagnetized, torque will be produced even when the electromagnetic solenoid is powered off, and a fail-safe function will also be achieved. Can be secured.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a schematic configuration of an electric servo motor section in a guide vane control device of the present invention, FIG. 2 is an enlarged sectional view of a reduction gear unit, and FIG. 3 is a schematic configuration diagram of a conventional electric servo motor section. FIG. 4 is a diagram showing the opening degree-closing force characteristics of the guide vane. DESCRIPTION OF SYMBOLS 1... Electric motor, 1a... Output shaft, 3... Ball screw pongee, 4... Operating rod for opening/closing guide vane, 5... Reduction device, 6.8-... Belt wheel, 6a, 6b , 8a, 8
b-Fl cone plate, 10...belt, 11.12...electromagnetic solenoid.

Claims (1)

[Claims] The output shaft of the electric motor and the ball screw shaft to which the operating rod for opening and closing the guide vane is threaded are connected via a speed reduction device consisting of a variable V-type belt wheel that changes the working diameter of the belt by changing the interval between mutually opposing conical plates. A water turbine guide vane control device characterized by interlocking connections.